Campus Units

Materials Science and Engineering, Ames Laboratory

Document Type

Article

Publication Version

Accepted Manuscript

Publication Date

5-2017

Journal or Book Title

Journal of Forensic Sciences

Volume

62

Issue

3

First Page

612

Last Page

618

DOI

10.1111/1556-4029.13342

Abstract

Numerous studies have focused on determining whether objective statistical methods can be used to discriminate between known matches and nonmatches when comparing laboratory prepared toolmarks. This study involved an analysis of striated toolmarks made as a function of varying vertical and horizontal angles of attack. Comparisons based on experimental data show that replicate toolmarks from the same tool show high correlation values at identical vertical and horizontal angles, with the correlation decreasing as the angular difference increases, especially for horizontal angular changes. Comparisons between nonmatching samples produce low correlation values that remain unchanged as horizontal angular differences increase. While complete statistical separation was not achieved between matching and nonmatching samples, there is evidence demonstrating that toolmarks can be identified if the variation in horizontal angle is within 10°. The experiment shows that computer‐aided comparison techniques could be viable for identification with the proper statistical algorithm.

Comments

This is the peer-reviewed version of the following article: Macziewski, Chad, Ryan Spotts, and Scott Chumbley. "Validation of Toolmark comparisons made at different vertical and horizontal angles." Journal of Forensic Sciences 62, no. 3 (2017): 612-618., which has been published in final form at DOI: 10.1111/1556-4029.13342. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. Posted with permission.

Copyright Owner

American Academy of Forensic Sciences

Language

en

File Format

application/pdf

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